These days, the current usual haking system is in danger because new cheating method was discovered ( this ).
So let me share my ideas for the hacking system instead of the current one.

Current hacking system

• Contestants can hack the codes of other contestants in the same room during the coding phase.
• Contestants who can't solve a task or who don't lock their solution can't make hacking attempts at the task.
• Successful: +100pts
• Unsuccessful: -50pts

Suggestion 1: Open hacking system(long)

• Contestants can hack the codes of any other contestants, Like edu.
• Hacking has around 12h, and no points will be awarded.
• Any contestants can make hacking attempts on any submissions.
• Users can copy and execute the codes by themselves.
• The only benefit for contestants is reducing other contestants' scores.

Suggestion 2: Open hacking system(short)

• Exactly the same as Suggestion 1, except for the length of the hacking phase.
• The length of the hacking phase is around 30min, at most 60min
  • these lengths are just my idea

Suggestion 3: Room-division hacking phase

• Contestants can hack the codes of other contestants in the same room, but it's not at the coding phase but at a hacking phase separated from the coding phase.
• Duration is 30min or 15min.
  • maybe uncopiable 30min or copiable 15min is good?
• Any contestants can make hacking attempts on any submissions in the same room.
• Successful: +100pts
• Unsuccessful: -50pts

Suggestion 4: Room-free hacking phase

• Any contestants are presented with about min(20,AC count for the problem) submissions (chosen equally, randomly, independently) for each problem.
• Duration is 30min or 15min.
  • maybe uncopiable 30min or copiable 15min is good?
• Any contestants can make hacking attempts on any submissions which are presented by the contestants.
• Successful: +100pts
• Unsuccessful: -50pts

Suggestion 5: Removing the hacking system

• Nowadays tests are strong enough(really?) and hacking is a thing of the past.
• Then, why not remove the hacking feature?

All of my suggestions are preventing to see other contestants' codes during the coding phase, but there may be some ideas to do coding and hacking in parallel like now.
Feel free to share your idea. I'll add them to the list.